The present invention relates to a method of frame synchronization in a digital data transmission. The present invention also relates to a frame synchronization system that embodies the method of this invention.
In frame synchronization systems, particularly for critical applications, such as in military applications, it is becoming more important to use a scheme wherein the transmitted data (traffic) can not be easily deciphered or decoded by an eavesdropper. In this regard, a typical data transmission sequence is composed of consecutive frames of traffic data (bits) and an overhead word (bits). It is furthermore typical to provide, usually as part of the overhead word, a frame synchronization signal, usually of multiple bits disposed at the same position of each frame, usually at the start position of a frame. With such a fixed position synchronization word, there is not the level of security that one would like to see. Also, existing techniques may be susceptible to a loss of synchronization, and are, furthermore, not well adapted to provide rapid re-synchronization.
Accordingly, it is an object of the present invention to provide a method and system of frame synchronization in a digital data transmission and in which there is practiced a scheme that enhances the security of the transmission.